The invention relates to a cartridge or unit seal for sealing about a shaft rotatable relative thereto.
A known cartridge seal has an outer ring and an inner ring. The outer ring has an elastically-resilient sealing lip which bears, elastically prestressed, on the inner ring and a radial supporting surface which extends toward the sealing lip and is resiliently snapped into holding surface of the inner ring with space therebetween for relative rotation of the rings. At least one of the supporting and holding surfaces extends all the way around its ring to hold the relatively-rotatable rings together as a cartridge.
A cartridge seal of this type is disclosed in German Pat. No. 25 00 099. It has the sealing lip of the outer ring bearing on an axially-extending abutment surface on one side of the inner ring and a rubber-elastic intermediate layer on the other side of the inner ring securing the inner ring sealingly in position about the surface of a shaft. The sealing efficiency so obtained is less than satisfactory, however, particularly when high shaft speeds and/or radial shaft excursions occur in normal operation.